1. Field of the Invention
The present invention relates to an optical lens, a lens unit, an imaging module, an electronic apparatus, an injection molding mold, and an injection molding method, and particularly relates to an optical lens which is molded by an injection molding method.
2. Description of the Related Art
In recent years, most smartphones (multi-function mobile phones), mobile phones, tablet terminals, and the like have had cameras. Camera-equipped smartphones and the like are equipped with a small and thin imaging module. The imaging module has a structure where a lens unit and an imaging element unit are incorporated. The lens unit has a built-in optical lens. The imaging element unit has a built-in imaging element such as a charge coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor. Further, in most cases, in the lens unit, a plurality of optical lenses may be used in combination.
Some optical lenses used in cameras of smartphones, mobile phones, tablet terminals, and the like are made of resin (for example, a thermoplastic resin), and are manufactured by an injection molding method.
Here, the injection molding method is one of methods of molding resin. In the injection molding method, first, resin is injected into a cavity of a mold (injection molding mold) having a predetermined shape, and the cavity is filled with the resin. Thereafter, by cooling down the injection molding mold, the resin with which the cavity is filled is cooled down and solidified. In such a manner, in the injection molding method, it is possible to obtain a molded article having the same shape as that of the cavity of the injection molding mold.
JP2010-14983A and US2013/0148208A describe a technique relating to an optical lens of a resin which is obtained by an injection molding method.
JP2010-14983A describes a technique for solving a problem that an optical axis of an optical function portion of an optical lens deviates from a direction of reflection on a mirror surface portion provided on a flange portion.
US2013/0148208A describes a technique for preventing weld lines and voids from occurring in an optical function portion of an optical lens.